"He wasn't held out," coach Jim Schwartz said. "He was out there working. We just limited his reps. We limited a decent number of guys today. A lot of them are nursing some things -- not enough to keep them out of an entire practice, but also not enough that you want to push through an entire practice.

"This was somewhere in between. (Houston's) fine."

Houston also missed a day of practice last week with migraines, which he said are hereditary.

Veteran cornerback Ron Bartell took Houston's place with the first team Sunday, and Chris Greenwood got at least two rotations with the starters as well. Schwartz downplayed the significance of Greenwood's role there, saying it was just a matter of rotations, but it's still believed to be his first run of any kind with the starters.

Rookie Darius Slay worked with the first team the whole way for the second consecutive practice, and appears like a good bet to start over Bartell on Thursday against the New England Patriot.

Another defensive back, Louis Delmas, missed yet another practice but appears to be nearing a return. Schwartz said he hopes Delmas will rejoin the team Monday.

He hasn't practiced since before the preseason opener due to bad knees, but Schwartz maintained there have been no setbacks.

Other players who missed practice Sunday include linebacker Cory Greenwood (neck), new defensive tackle John Drew, defensive back Ross Weaver and defensive end Jason Jones (knee).